It is starting to happen all over the country right now. The West Nile Virus (WNV) is testing positive in mosquitoes almost everywhere throughout the U.S. Only one human case has been reported in the state in Cleveland County, according to the Oklahoma State Department of Health.

According to the Oklahoma State Department of Health's website, persons of any age can become ill after an infected mosquito feeds off of a human. But those of greatest risk are people 50 years old and above who can potentially develop a serious illness involving the nervous system.

Those who become ill may experience mild symptoms to severe symptoms, such as a fever, headache, fatigue, body aches, trunk and body rash or in more severe cases the illness can lead to the development of meningitis or other neurological diseases.

The transmission of the virus varies among different species of mosquitoes.

“Nuisance mosquitoes” are the type that hatch after severe flooding and aggressively bites their host, leaving behind a lot of itchy bites.

They are not typically known to transmit any diseases though.

These populations tend to die off approximately three weeks after rain stops and low-lying areas dry up.

The Culex species are the ones to be on guard for since they are the primary vector of WNV. They feed on infected birds and transmit the virus when biting humans, horses and other mammals. The Culex species has a lifespan of 10-14 days and usually breeds in waters free from plant life. That population increases during the mid-to-late summer, usually starting in July and ending in October.

There were 35 people infected with the virus last year, but no reported deaths. In 2015, the state received 89 reported cases and confirmed 10 deaths due to WNV.

Unlike the nuisance mosquitoes, Culex mosquitoes multiply during increasingly hot dry weather.

Since Oklahoma became invaded by the virus years ago, there have been three outbreak years — 2003, 2007 and 2012 — recorded during higher than normal summer temperatures and drought.

Very few mosquitoes are infected with the virus, even in areas where the virus is present. OSDH noted on their website that nearly 80 percent never become ill from WNV after being bitten.

Anyone experiencing symptoms such as intense headache, dizziness, stiff neck, severe weakness, muscle tremors, confusion, or seizures should visit a healthcare professional immediately.

There are several ways to take precautions against these bloodsuckers.

Applying insect repellent containing the proper active ingredients to exposed skin and clothing when outdoors — especially during the evening and early morning hours — proves to be effective in repelling the pests. More information can be found at www.ok.gov/health/.